Question

The number and type of bonds between two carbon atoms in $CaC_2$ are

• A. one sigma($\sigma$)and one pi($\pi$)bonds
• B. one sigma($\sigma$)and two pi($\pi$)bonds
• C. one sigma($\sigma$)and one and a half pi($\pi$)bonds
• D. one sigma($\sigma$)bond

Answer 1

Answer: (B)

In $\mathrm{CaC}_{2}$ we have $\mathrm{Ca}^{2+}$ and $\mathrm{C}_{2}^{2-}$ which are held together by ionic bonds. The structure of $\mathrm{C}_{2}^{2-}$ is $[\mathrm{C} \equiv \mathrm{C}]^{2-}$, thus it contains one $\sigma$ - and two $\pi$ -bonds between two carbon atoms.